Process of finishing metal sheets or plates



l/VILLIAM MILTON THEOBALD, OF WELLSVILLE, OHIO.

PROCESS OF FINISHINGMETAL SHEETS OR PLATES SPECIFICATION forming part of Letters Patent No. 627,022, dated June 13, 1899.

Original application filed June 7, 1898, Serial No. 682,841. Divided and this application filed November 9, 1898- Serial N6- 695,977. (No specimens.)

To all whom, it may concern:

Be it known that 1, WILLIAM MILTON THEO- BALD, a citizen of the United States, residing at IVellsville, in the county of Oolumbiana and State of Ohio, have invented certain new and useful Improvements in Processes of Finishin g Metal Plates or Sheets; and Ido declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In an application for patent filed by me June 7, 1898, Serial No. 682,841, I described and claimed the invention set forth in the following specification and claims, Which forms a divisional application of that above referred to.

I will now proceed to describe the invention which forms the subject-matter of the present application for patent and which was disclosed in the original application above referred to.

My invention relates to an improved process of finishing metal sheets or plates; and the object is to obtain a more uniform blue or black color of the sheets or plates.

To this end the invention consists in the 'process hereinafter more fully described, and

particularly specified in the claims.

In annealing metal sheets or plates the same are placed upon the annealing pan or bottom and covered by the annealin g-box, after which the box and pan are luted in the usual manner to prevent the ingress of air to the sheets or plates, which would result in excessive oxidation. The annealing-box and its contents are now charged into a suitable furnace and brought to the proper or desired degree of heat, approximately 1,4t00 Fahrenheit. This completes the first step of my process.

In the second and improved step of my process after I have removed thesheets or plates one or more at a time from the annealing-box I expose them to the air until the desired degree of oxidation has been attained, and

then cover them with any suitable covering, such as an annealing-box, to prevent further oxidation, thereby securing a uniform color.

If it be desired to give to the sheets or plates a gloss or high polish or to smooth them, I take them from the box in which they are cooled to smoothing rolls, where these effects are secured. This step is not always necessary, as the trade sometimes prefers the sheets in the rough without gloss or finish.

Having thus described my invention, What I claim, and desire to secure by Letters Patent, is=

1. The process herein described of preparing metal sheets or plates, which consists in annealing said plates free from contact with atmospheric air cooling the plates free from atmospheric air to a temperature ranging be tween the annealing degree of heat and about 900 Fahrenheit, subjecting said sheets or plates to the atmospheric air to oxidize them; a

then excluding the air therefrom to prevent further oxidation, in which condition they are left to cool off, substantially as set forth.

2. The process herein described of preparing metal sheets or plates, which consists in annealing said plates free from contact with atmospheric air; cooling the plates free from atmospheric air to a temperature ranging between the annealing degree of heat and about 900 Fahrenheit, subjecting said sheets or plates to the atmospheric air to oxidize them;

then excluding the air therefrom to prevent I 

